You could categorise on the basis of a high went to river but low WtSD% - and call him the 'chaser' - the problem is that you would need an extra category and a lot of hands played to be certain of this player type and I'm not sure it would alter your best play.
He will be classed as a 'fish' by default. So you would bet into him. This would be the right thing to do - you might be doing it because you expect him to fold, but it's still the correct thing to do if you knew he was in fact a chaser...
When you say Loose Aggressive or Tight Passive I'm not sure what you mean exactly.
None of the passive post-flop players are winning types (OK individual players who can read well or are slowplayers in a garden of maniacs may be winning players, but as a strategy post flop passivity sucks).
In contrast almost all the post-flop agressives are winning types - ABC,TPA, TAA, sLPA, sLAA - anyone less than 35% Vp$iP with a decent PFA can expect to win a bit..
Even LAA, LPA do ok unless out and out maniacs.
By contrast the post-flop, passives have a dreadful time - CS, TPP, TAP, sLAP, sLPP, LAP, LPP - these guys lose...TPP's lose less but they still don't outrun the rake..
Now what you are saying is that in small sample sizes this is self-selected for strong hands- get strong hand/good flop-bet or raise more - win - be shown as aggressive and winning - get slightly weaker hands/worse flops call more (as you point out folding doesn't actually affect the stats)- be shown as more passive
I do recognise this as true to some extent (which is why I do point it out in 2a). I'm all ears as to how to try to take it into account other than noticing that as you filter by more and more hands played the winners stay winners ad the losers stay losers and the nos don't move much - the only exception is maniacs who move from losers to winners between 20 and 50 hands - but that's because a far more powerful self-selection is going on - they self-select for luck - they double up or bust - the ones left at 50 are lucky and rich and a small fraction of those that started out..
I think if you are going to use GT+ at all for folks who have played less than 200+ hands you have to make some assumptions and ignore issues like this to some extent.
The remarkable thing for regular users (as AP10 who play 15K hands/week says in the curent results bankroll thread) is just how good at predicting actions GT+ is. I find that pre-flop stats settle down after a few as 20 hands and that the post-flop ones are pretty solid from 40+. For every player with 35 hands played and a Vp$iP of 40%+ who is just hitting great starting hands, there are ten who are just loose. The evidence that the issue doesn't invalidate the stats isn't theoretical but empirical - it really works to predict outcomes very quickly..
It reminds me of a long debate I had when playing cricket once near a swarm of midges - I reckoned that maybe the wall of air moving in front of a cricket bat would move the midges out of the way if you swung it at them - they would disperse rather than be swatted. ...after 15 minutes on and off discussion one of the guys took the bat, waved it through the cloud of midges and we all saw the midge blood on it for ourselves...
Empirical testing - the core of scientific knowledge..